Sustainability Of Streaming: How Does OTT Compare With OTA? - Part 3

Parts 1 and 2 in this 3-part series analyzed the latest information about OTT and DTT energy consumption in the UK in the year 2021, concluding that there are important energy efficiency improvements to make in OTT, and some big decisions coming our way in DTT. Part 3 considers what some of the leading sustainability proponents in the OTA and OTT video distribution ecosystems are currently thinking about and doing to help.

OTT And DTT Efficiency Improvements

If we shift to a predominantly OTT model and see DTT reduce in size, then we will need energy efficiency improvements primarily in the expanding OTT delivery chain. We will also need energy reduction and efficiency improvements in the DTT delivery chain. How and when to do this are the big questions that need answering.

First, let’s assume that the big problem to solve is OTT’s less efficient Delivery Equipment position, that used 54Wh per device hour in the UK in 2021. This compared to the DTT result of 9.1Wh. A good target could be to reduce from 54Wh to 12.4Wh, through the following approach:

  • OTT CPE (Routers, Mesh networks, WiFi extenders) – reduce from 21Wh to 10Wh. As the home network is a must-have for general internet access, we cannot remove this component entirely and must optimize its energy consumption (see below).
  • OTT Peripherals (STB - set-top boxes) – reduce from 21Wh to 0Wh. As the STB is not 100% essential to the delivery of OTT video, it could be removed from the delivery chain.
  • OTT Network (CDN, Data Centers) – reduce from 12Wh to 2.4Wh. As CDN infrastructure can be optimized for the bandwidth hungry video use case, it is conceivable that a significant reduction could be achieved by switching to an optimized architecture.
  • DTT Network (Transmitters) – find improvements to go lower than 2.6Wh, based on driving efficiency measures in transmitters particularly while network usage is still very high.

Some of the industry’s thought leaders in this space have given their views on how some key elements can be improved to support our content delivery efficiency goals.

OTT CPE – Reducing From 21Wh To 10Wh Or Better

“There are a range of energy consumption improvements we can consider for consumer premise equipment (CPE),” says Dom Robinson, Founder of Greening of Streaming. “Power down standards for routers and TVs should be an industry standard. Traditional standby mode is very poorly defined across the industry and, in practice, means very different things to each vendor. Removing storage drives from millions of STBs is another option – on demand we can stream from central or cached locations. And we can reduce delivery speed in favor of more environmentally friendly delivery methods, which is the exact area of research to find practical solutions for the Greening of Streaming’s Working Group 1.”

OTT Networks – Reducing From 12Wh To 2.4Wh

MainStreaming has architected its CDN to be video-centric, which means we have optimized the hardware components and the software algorithms for video use cases,” says Sergio Carulli, Chief Innovation Officer at MainStreaming, a European-centric CDN service provider that is a founding member of the Greening of Streaming and has built its reputation on its “broadcast-grade streaming” capabilities. “We have already focused on achieving up to 50% energy consumption reductions through our new CDN architecture compared to a traditional general-purpose CDN by tuning the hardware architecture for video and designing the software to be more intelligent in managing content in a distributed Edge environment. We have also collaborated closely with Intel, another Greening of Streaming member, to ensure our latest generation of servers have significantly reduced power consumption compared to previous server generations. The overall impact of these two key changes is significant, and it’s just the beginning.”

DTT Network – Improvements Beyond 2.6Wh

Today, the UK’s broadcast network operated by Arqiva delivers about 90% of the viewing hours of the UK’s leading broadcasters that reaches over 38 million people. That technology must be as efficient as feasible, and it is possible that the DTT platform could be made more efficient through upgrades to more energy-efficient technology that will reduce energy loss in the transmission process (in 2021, DTT delivery services in the UK consumed about 73GWh, see Article 2, Figure 3). In parallel, Arqiva has recognized the energy efficiency concerns related to video streaming expressed by their customers in the UK and other European markets. Arqiva recently announced a new collaboration with MainStreaming to develop more energy efficient streaming platforms that also meet the performance, cost, and scale requirements of media businesses, particularly broadcasters with live streaming services.

If the above energy efficiency gains are achieved, then an OTT-only world would use approximately 3,300 GWh in the UK, a 23% reduction compared to the 2021 usage level of 4,300 GWh (see Article 2, Figure 4) for combined OTT and DTT delivery. The DTT environment would see an overall energy consumption reduction from the above efforts, reducing the 90GWh that is currently consumed annually. The in-depth studies that will take place over the coming years will clearly need to show us exactly how far we can reduce the total energy consumption of our media delivery ecosystems.

Given the likely scenario in the coming 10 years that we will move closer to the OTT-only world, some questions will need answering to map this course out sensibly. Would OTT-only be first focused on major urban areas where internet access is easier to deliver?  Would the existing broadcast network be converted to support other communication use cases?  Would broadband services be subsidized for people who would otherwise not be able to afford them?  There are some really big questions to figure out as the whole media industry drives towards highly sustainable practices and whole populations adjust their viewing methods and habits.

Making Streaming Sustainable

The studies referenced so far have used the attribution method, allocating electricity usage to OTT and DTT primarily based on viewership. In the OTT analyses, there are many system components that are not clearly identified in the studies, and averages have been used (e.g., average bitrate based only on Netflix’s average in 2021) which hides the impact of different choices we make as consumers, for example to watch a UHD vs. HD stream on our SmartTVs or on our laptops. A top-level priority for our sustainability efforts is to make our measurement more precise, in order to better inform our future sustainability actions in the M&E and Technology industries, and to provide the best possible consumer advice for reducing CO2e emissions.

Greening of Streaming, a new member association for the global internet streaming industry, was founded to shine a bright light on the issue of how to make OTT sustainable. The organization’s mission statement says they exist to “create joined up thinking around end-to-end energy efficiency in the technical supply chain underpinning streaming services”.

Dom Robinson, founder of Greening of Streaming, explains the original thinking behind the founding of the association: “There is a direct link between consumer behavior and energy consumption, which is made real for all of us by the receipt of an energy bill based on energy used. This simple concept of knowing how much energy is consumed by streaming is vital for our work to make streaming as sustainable as it must be. At an engineering level, a focus on wattage is helpful, because it is a metric around which all engineers can cooperate. CO2e is obviously the end goal for us, but practical actions that reduce CO2e first come from reducing energy consumption.”

Improving How We Measure

A key objective at Greening of Streaming is to clearly define how to measure energy consumed for streaming delivery. We can understand how much energy the equipment uses from lab tests and field tests, but how much all of the delivery networks, servers, routers, and other devices use to actually deliver the content that we consume is not well understood.

The diagram in Figure 1 of the path taken by a video stream helps engineers across the video streaming chain to discuss and reach consensus on how to measure energy consumption - for delivering live video, VOD, and for understanding what happens exactly when infrastructure is not being utilized. This view applies equally to OTT, CableTV and IPTV, which are all part of the IP video delivery domain, and therefore the “video streaming domain”. This basis of shared understanding will help the content distribution industry to establish benchmarks and improvement plans that can be supported by all the technology businesses working on video streaming.

Figure 1: Streaming Video Delivery Chain (source: Greening of Streaming).

The Watt-based metric is also important to clearly state actual energy consumption, regardless of the source of the energy. Each country around the world has a different CO2e conversion metric – as noted in Article 2, the UK’s was 0.29130 in 2021, based on the sources of energy. Of course, the overall goal is for this figure to reduce as we use more renewable energy sources. But as this is outside the control of engineers working in video streaming, it is essential to work with the controllable unit of energy consumption – watts.

Improvements To Consider Now

The right measurement approach will clearly support the achievement of long-term sustainability objectives. But even without the precise measures we will have in the future, there are already some clear subjects to address, which form part of other Greening of Streaming working groups. The following are some of the key questions the working groups are addressing:

  • Video formats and bitrates – what quality of video should be a consumer standard to drive optimal delivery efficiency? How do we enable consumers to opt in (rather than need to opt out) to watch the most energy-consuming formats?
  • CDN architectures – are CDN architectures energy-usage-optimized specifically for high-bandwidth video delivery? Are content caching strategies streamlined to minimize the need for multiple copies of the same file? Can we manage with less over-provisioning of delivery capacity and still meet stringent delivery SLAs?
  • Equipment life cycles – how can we ensure hardware technology is efficient over longer periods of time? Can FPGAs and programmable soft systems and semi-soft systems extend hardware lifetimes longer, while also remaining highly efficient?
  • Fitting capacity to available energy – what capacity availability SLAs and contracts are necessary for streaming platform services? How should we ensure capacity is geographically located to align with efficient energy provision? Can we engineer content delivery infrastructure to function according to the available and most efficient energy supply?
  • Video delivery methods – multicast and unicast methods could be combined to find optimal efficiencies in the end-to-end delivery infrastructure spanning live streaming and on-demand streaming, but is there an optimal blueprint for the industry?

These questions, and others, will drive forward the work of Greening of Streaming in the years ahead, and all members of the Streaming industry are encouraged to participate to share knowledge. The ethos is clear – in sustainability we cannot compete with each other to win, but instead we need to collaborate with each other to win. The only way to win is together.

Sustainable Content Distribution

The latest information from industry reports and leading thinkers makes it clear that we must work out how to use less energy in the distribution of video. Whether we are using DTT or OTT platforms to deliver the content, the mission is to become more energy efficient.

DTT is the most efficient method today but can be more efficient by accelerating technology upgrades. However, as network utilization declines, efficiency is likely to worsen, which will need to be addressed. OTT is growing and therefore needs to receive particular focus to improve its energy efficiency. Greening of Streaming, and many technology companies, service providers, and broadcasters are all doing their part to achieve our collective NetZero objectives.

The most radical solutions of completely switching off certain methods of content delivery are unlikely to happen quickly. A complete DTT switch-off in the near-term is highly unlikely while we support many millions of people on the planet to receive content, and as we improve the performance, reliability, and security of OTT-based delivery. But we should be prepared for an OTT-centric world.

Ultimately, there needs to be strong collaboration between broadcasters, CDNs, ISPs and equipment manufacturers, who collectively are accountable for the efficiency of our content distribution platforms. Video distribution hyper-scaler service providers like Arqiva can provide a strong, central focal point for managing cross-industry multi-platform evolution. As we migrate from a DTT world to an OTT world over the years ahead, we need to find all the ways to collaborate that we possibly can to make content distribution more energy-efficient.

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